- 2 Tbls. butter
- 2 medium fennel bulbs, green tops removed
- 4 garlic cloves, minced
- 2 medium leeks, sliced thin, white parts only
- 1 tsp. fresh thyme leaves
- 1 tsp. granulated sugar
- 8 ounces Fontina shredded
- 1 package puff pastry squares
- Heat the oven to 400°F and arrange a rack in the middle.
- Prepare the fennel by quartering it lengthwise, removing the core, and then slicing the fennel quarters crosswise into thin (about 1/8-inch) slices.
- Heat butter in a large skillet over medium heat. Add the fennel, leeks and garlic. Season well with salt and pepper, thyme, and sugar and stir to coat.
- Cook, stirring occasionally, until fennel is golden brown and fork tender, 8-10 minutes. Remove from heat and set aside to cool slightly. (This can be done up to 3 days in advance.)
- Place the puff pastry squares on a parchment-lined cookie sheet. Top each square with 1/4 cup of fennel leek mixture and 1/4 cup of cheese.
- Bake in the oven for 15 to 20 minutes, until the tops of the tartlets are golden brown, and the puff pastry is cooked through. Cut into triangles and serve immediately.